I found this weird thing weeks (maybe months) ago. Actually this is a helpful bug, but I don't think it is supposed to be like that. So the whole bug is all about seeing other player's champions, mastery levels and earned crates. Everything you need to know is in the video.
**Server:** EUNE (I guess it works on other regions as well)
**Type of Bug:** Summoner profile --> champions
**Details:** To recreate this bug you just need to do these steps down below.
**1.** Open a summoner profile just to see his/her most played champions.
**2.** Go to your profile and press Champions tab as fast as you can. (This only works if you do it fast)
**3.** You should see that player champions and his/her progress.
**Video:** Just click [here](https://www.youtube.com/watch?v=dIT7pRxjYDM) to open the video.
**Expected result:** Seeable champion progresses from other players.
**Observed result:** I saw other summoner's champion progresses.
**Reproduction rate:** 10/10 - happens every single time.
If you do the second step slowly, it will work as it supposed to be.
(This is my first report, so sorry if I did something wrong, and sorry for my English, it isn't my native language.)